Backing sheet



Patented Aug. 18, 1925.

UNITED STATES PATENT OFFICE.

BACKING SHEET.

No Drawing.

'To all whom it may concern:

Beit known that I, HARRY E. SMITH, a citizen of the United States, and resident of South Orange, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Backing Sheets,

of which the following is a specification. This invention relates to an improved backing or carrying sheet for stencils of a type which is in large use and consists generally of a thin porous paper, such as Japanese yoshino, which is coated or impregnated with a compound havinga gelatinous basev These stencils are ordinarily written upon by the bare type of a typewriter, which action removes the coating so as to permit the ink to pass through where the type has struck when the stencil is subsequently run through a printing machine, whereby the typewritteninscription may be reproduced in multiple copies as desired.

These stencil sheets are commonly associated with a relatively hea backing,

which} is used while'the stencil is beingwritten in the typewriting machine, and removed from the stencil when the latter is put in the printing machine. .It is the obect ofmy invention to improve upon this kind of backing, particularly in the way of I providing a backing sheet that assists in preserving the stencil, provides a slightly yielding surface to receive the impact of the type of the typewriter and thereby improve the cutting or writing of the stencil, increases the visibility or legibility of the inscription' being written on the stencil sheet, and prevents the stencil from adherin to the backing. 1

in preparing the backing 1 preferably 40 select a relatively heavy paper of goo quality, such ion instance, as-a good grade of manila jute paper, approximately SIX or seven one thousandths of an inch in thickness.

This paper is coated on one side with varnish or shellac, which operation is preferably performed by any well known or approved varnishing machine such, for' instance, as one in which the Varnish'is applied to the paper by means of rollers. This operation is Well understood in the art and need not be further described.

After the varnish has dried, I apply a layer of wax on top of the layer of varnish. By preference I select a parafiin wax hav- 5 article as thus made.

Application filed January 11, 1923. Serial No.612,082.

ing a melting point of, say, one hundred and twenty to one hundred and thirty degrees Fahrenheit, although my invention is not limited to the employment of this particular wax. The wax is melted in any suitable manner and is applied to the varnish layer on the paper by means of rollers or any other satisfactory distributing device or apparatus. The wax is then permitted to dry,

and the backing sheet is complete.

The stencil sheet may be secured to one end of the backing sheet in the ordinary manner, well understood in the art, and the backing may be used while the. stencil is absorbing the wax, while t e wax layer, on

top of the varnish, provides this backing sheet with the advanta us features above mentioned as well as 0t ers inherent in the The increase in visibility or legibility duringthe operation of type to be formed in the stencil somewhat greater in width of line than if the wax were not employed. The wax is also of a preservative nature and tends to substan-\ tially increase the life of the stencil. 'The type, thereby permitting the letters on the presence, of the wax layer between the I stencil and the varnish, also prevents any stickingof the relatively frail stencil sheet (1 to the varnish on the backing, which sticking, if it occurred, might occasion injury to the stencil while being separated from the backing.

Backing sheets for this same purpose have been manufactured and, used on a large scale, but it has been found desirable, if not necessary, to interpose a third sheet of material between said backing and the stencils. My invention obviates theinecessity or desirability of this third sheet, and, at the same time, produces a more effective backing. and, therefore, a better resultin the stencil. 3

It will be understood that various changes may be resorted to in the material, composition and method of manufacture without departing from the spirit and scope of my invention; hence, I do not intend to be limited to the details herein described exce t asthey are set forth in the claims.

hat I claim is 1. In combination with a stencil sheet, a backing therefor, said backing comprising, a flexible sheet having a water repellant coating and a yielding and preservative coating on said water repellant coating, whereby said stencil sheet can rest directly upon and obtain the benefits of said yielding and preservative coating.

2. In combination with a stencil sheet, a backing therefor, said backing comprising, a sheet of paper having a water repellant coating and a yielding and preservative coating on said water repellant coating whereby said stencil sheet can rest directly upon and obtain the benefits of said yielding and preservative coating.

3. In combination with a stencil sheet, a backing therefor, said backing comprising, a flexible sheet having a coating of varnish and a coating of wax on the varnish, whereby said stencil sheet can rest directly upon and obtain the benefits ofsaid coating of wax.

4. In combination with a stencil sheet, a backing therefor,said backing comprising, a sheet of paper having a coating of varnish and a coating of wax on the varnish, whereby said stencil sheet can rest directly upon and obtain the benefits of said coating of wax.

5. In combination with a stencil sheet, a backing therefor, said backing comprising, a flexible sheet having a coating of varnish and a coating of paraflin on the varnish, whereby said stencil sheet can rest directly upon and obtain the benefits of said coating of parafiin.

6. In combination with a stencil sheet, a backing therefor, said backing comprising, a sheet of paper having a coating of varnish and a coating of paraffin on the varnish, whereby said stencil sheet can rest directly upon and obtain the benefits of said coating of arafiin.

n testimony that I claim the foregoing as my invention I have signed my name this tenth day of January, 1923.

HARRY E. SMITH. 

